With the cost of handheld electronic devices decreasing and large demand for digital content, creative works that have once been published on printed media are increasingly becoming available as digital media. For example, digital books (also known as “e-books”) are increasingly popular, along with specialized handheld electronic devices known as e-book readers (or “e-readers”). Also, other handheld devices, such as tablet computers and smart phones, although not designed solely as e-readers, have the capability to be operated as e-readers.
A common standard by which e-books are formatted is the EPUB standard (short for “electronic publication”), which is a free and open e-book standard by the International Digital Publishing Forum (IDPF). An EPUB file uses XHTML 1.1 (or DTBook) to construct the content of a book. Styling and layout are performed using a subset of CSS, referred to as OPS Style Sheets.
For some written works, especially those that become popular, an audio version of the written work is created. For example, a recording of a famous individual (or one with a pleasant voice) reading a written work is created and made available for purchase, whether online or in a brick and mortar store.
It is not uncommon for consumers to purchase both an e-book and an audio version (or “audio book”) of the e-book. In some cases, a user reads the entirety of an e-book and then desires to listen to the audio book. In other cases, a user transitions between reading and listening to the book, based on the user's circumstances. For example, while engaging in sports or driving during a commute, the user will tend to listen to the audio version of the book. On the other hand, when lounging in a sofa-chair prior to bed, the user will tend to read the e-book version of the book. Unfortunately, such transitions can be painful, since the user must remember where she stopped in the e-book and manually locate where to begin in the audio book, or visa-versa. Even if the user remembers clearly what was happening in the book where the user left off, such transitions can still be painful because knowing what is happening does not necessarily make it easy to find the portion of an eBook or audio book that corresponds to those happenings. Thus, switching between an e-book and an audio book may be extremely time-consuming.
The specification “EPUB Media Overlays 3.0” defines a usage of SMIL (Synchronized Multimedia Integration Language), the Package Document, the EPUB Style Sheet, and the EPUB Content Document for representation of synchronized text and audio publications. A pre-recorded narration of a publication can be represented as a series of audio clips, each corresponding to part of the text. Each single audio clip, in the series of audio clips that make up a pre-recorded narration, typically represents a single phrase or paragraph, but infers no order relative to the other clips or to the text of a document. Media Overlays solve this problem of synchronization by tying the structured audio narration to its corresponding text in the EPUB Content Document using SMIL markup. Media Overlays are a simplified subset of SMIL 3.0 that allow the playback sequence of these clips to be defined.
Unfortunately, creating Media Overlay files is largely a manual process. Consequently, the granularity of the mapping between audio and textual versions of a work is very coarse. For example, a media overlay file may associate the beginning of each paragraph in an e-book with a corresponding location in an audio version of the book. The reason that media overlay files, especially for novels, do not contain a mapping at any finer level of granularity, such as on a word-by-word basis, is that creating such a highly granular media overlay file might take countless hours in human labor.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.